Reinsurance and Other Monoline Exposures - Effect of Reinsurance on Statement of Operations (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Premiums Written:
Direct									$ 116		$ 106		$ 244
Assumed									(12)	[1]	17	[1]	9	[1]
Ceded									15	[2]	2	[2]	51	[2]
Net									119		125		304
Premiums Earned:
Direct									581		819		936
Assumed									47		40		50
Ceded									(58)		(107)		(133)
Net earned premiums	158	144	136	132	182	159	163	248	570		752		853
Loss and LAE:
Direct									132		110		636
Assumed									37		73		(4)
Ceded									(43)		(29)		(128)
Loss and LAE	$ 72	$ (44)	$ 57	$ 41	$ 85	$ 55	$ 62	$ (48)	$ 126		$ 154		$ 504

[1] Negative assumed premiums written were due to cancellations and changes in expected Debt Service schedules.

[2] Positive ceded premiums written were due to commutations and changes in expected Debt Service schedules.